Fuel characteristics that all biodiesel users should understand
Fuel hoses
When blend levels higher than B20 are used in vehicles built before 1993, biodiesel can cause material degradation of fuel hoses and fuel pump seals. This degradation occurs very slowly and can be monitored by regularly checking fuel lines for dampness. To prevent fuel line deterioration, rubber hoses may be replaced with synthetic hoses like Viton. Most vehicles manufactured after 1993 have been built with synthetic hoses and seals that are biodiesel compatible.
Fuel filters
Biodiesel has solvent properties, and it actually cleans your injectors and fuel lines as it travels through the fuel system. As you begin using blends of biodiesel higher than B20 in older vehicles, you should anticipate having to change your fuel filters a few times as old petrodiesel deposits are dislodged. If your fuel filters begin to catch a large amount of material, you will notice a decline in performance and your vehicle will feel sluggish. Clean Energy Biofuels recommends carrying an extra set of fuel filters in your vehicle as a backup.
Cold Weather
Like petrodiesel, biodiesel clouds up and eventually gels at colder temperatures. This means that the fuel begins to solidify, making it harder for your vehicle to pump fuel and even to start. Biodiesel’s gel point depends on what it was made from, but generally the gel point of B100 is around 32°F. Because the gel point of biodiesel is higher than that of petrodiesel, many biodiesel users decrease the concentration of biodiesel in their fuel during the winter according to the region in which they live. Biodiesel’s gel point can also be lowered using cold-flow fuel additives similar to those used with petrodiesel fuel.
Warranty
While many automakers recognize the value of commercially-produced biodiesel, most engine manufacturers only include biodiesel usage in the US under warranty at low blend levels (B5-B20). One reason for this is that engine manufacturers are not convinced that there is adequate quality control in the US’s young biodiesel industry. Even though commercially-produced biodiesel is required to meet ASTM specifications before it may be sold, many cases of biodiesel producers selling off-spec fuel have been uncovered. Please also read the section on Fuel Quality.
